1 If you ever travel to San Francisco, you can take a ride on a cable car. These colorful vehicles, which look a little bit like passenger train cars, carry riders up and down San Francisco's steep hills. People from all over the world make sure to take a ride on a San Francisco cable car when they visit California.2 Cable cars are unusual because they do not run under their own power. Cable cars run on rails, like a train, but in between the rails there is a slot where a strong cable is located. The cable is connected to an engine in the powerhouse, and it is kept moving all the time. The train itself has two cars. Passengers ride in the larger car. The train is operated from the smaller car, called a dummy, or a grip car. The grips are like a pair of large pliers. The operator closes the grips onto the cable to let the cable pull the train. To stop the train, he opens the grips and also sets the brakes. The first cable cars were operated by four or five men. One man operated a lever that controlled the grips, and the other four manned the brakes.3 In the 1880s and 1890s, cable cars were the most popular mode of transportation in San Francisco and other cities, especially those with steep hills. Cities all across the U.S., from California to New York, built cable car lines. So did other countries. Cable cars could travel steep hills that horse-drawn cars had never been able to manage. Cable cars could run all day. Unlike horses, they never needed to stop for food or a rest. They never left a mess in the streets, either.